The present invention relates to a rigid hinged-lid packet for elongated items, particularly cigarettes.
In the following description, specific reference is made to a rigid hinged-lid packet for cigarettes purely by way of example.
In the tobacco industry, packing machines are used for wrapping preformed groups of cigarettes inside respective foil wrappings, and conditioning the groups inside respective rigid packets, each comprising a cup-shaped hollow bottom container or body, and a cup-shaped top lid hinged to a top edge of the container so as to rotate between two positions respectively opening and closing the container.
Known rigid packets generally comprise a continuous rear wall divided into two parts by a virtual transverse hinge connecting the lid to the container; a front wall defined by two separate portions respectively constituting the front wall of the container and the front wall of the lid; and two lateral walls, each defined by a rear wing projecting laterally from the rear wall, and a front wing superimposed on the first and projecting laterally from the front wall. Like the front wall, each lateral wall is also defined by two separate portions respectively constituting the lateral wall of the container and the lateral wall of the lid.
Known rigid packets of the above type often present a U-shaped collar partly inserted inside the container, contacting the inner surface of the front wall and lateral walls of the container, and projecting upwards from the top edge of the container to partly engage the lid and prevent it from being accidentally opened when in the closed position.
On known packing machines, each rigid packet is formed by feeding the respective preformed group of cigarettes--already enclosed in the foil wrapping--through a loading station where it is combined with a respective U-shaped collar to form an assembly which, together with a respective blank, is fed to the input station of a wrapping wheel along which each blank is folded about the respective group of cigarettes to form a respective rigid hinged-lid packet.
Known packing machines therefore normally present two synchronized supply lines: one for the blanks, and the other for the collars.
To simplify the structure of known packing machines of the above type, and more specifically to eliminate the collar supply line, British Patent n. 2,151,212, for example, employs a blank wherein a free longitudinal end of an end panel, corresponding to the front wall of the container, is connected to the collar via the interposition of a longitudinal appendix; the collar comprises a central panel integral with the appendix, and two wings projecting laterally from the central panel; and the appendix of the blank is folded on to the inner surface of the end panel to define the front wall of the container complete with the collar.
Though it does in fact provide for eliminating the separate collar supply line, the above blank presents serious drawbacks due to the difficulty encountered on most known packing machines in folding the collar. On known packing machines, in fact, each blank, as it is fed forward on the wrapping wheel, is normally folded about the respective group in a succession of steps, the last one of which normally comprises folding the front wings on to the respective rear wings to complete the lateral walls of the packet.
In the case of a blank with a built-in collar as described in British Patent n. 2,151,212, the above final step would require radical alterations to known packing machines for producing rigid hinged-lid packets.